Hyperkeratosis, or scaling, is a very common symptom in skin disease, with around 150 genetic ichthyosis and ichthyosis-related skin diseases leading to this thickening of the outermost layer of the skin.

Topical delivery of keratin 10 mutation-specific siRNA-gold nanoparticles for epidermolytic ichthyosis
The blistering and thickening of skin seen in EI usually results from a change in a single letter of the DNA code (a mutation) in one copy of the gene that provides the codes for manufacture of a keratin protein in the upper layers of skin. Small interfering RNAs (siRNAs) are small pieces of genetic material that can identify DNA pieces and bind to them, preventing the gene from being translated into protein. siRNAs are able to distinguish the mutated DNA from the normal DNA, and thus are able to prevent only the abnormal keratin protein from being formed.

Epidermolytic ichthyosis (EI, or epidermolytic hyperkeratosis) is a rare inherited disease characterized by blistering in the suprabasal layers of epidermis. The affected patients suffer life-long problems from a stiff, painful, and malodorous skin that is easily infected. No drugs are known to significantly or consistently improve the widespread blistering and scaling in EI.

Generating immortalized cell lines and iPS cells from EI patients
There is no cure for epidermolytic ichthyosis (EI) (formerly called epidermolytic hyperkeratosis or EHK). Therefore, novel gene therapy approaches become extremely attractive for this inheritable epidermal disease caused by single gene mutations in either keratin 1 or 10. In order to permanently correct epidermal diseases, it is necessary to design a therapeutic approach that is able to correct epidermal stem cells. Preliminary studies with a pre-clinical mouse model for EI indicate the feasibility of ex vivo correction of mouse EI cells followed by reconstitution of the skin in a graft model. Before this approach can be tested in humans, it is desirable to first test this ex vivo gene therapy with human EI cells. For such purposes, large numbers of human EI cells are required.